[vtk-developers] STL in VTK Header Files

[Berk Geveci]

> Or maybe it is time to revise the coding standards? I don't know what the
> correct process is for doing this though.

I don't think that we need to revise this particular rule. It would be
confusing if it said "don't include STL headers UNLESS you have leaf
class or if it is a private header". I think that it is enough to
allow for exceptions. The same way we allow for exceptions to
including only the superclass' header in a .h file. Having rules that
are enforced blindly is never a good idea - there is almost always a
time when you have to break a rule.

I looked at the Python code that enforces the STL header rule and it
would be easy to change it to ignore cases like

 #include<vtkstd/vector> // STL include

-berk

On Mon, Jun 8, 2009 at 8:51 AM, Dave Partyka<dave.partyka at kitware.com> wrote:
> Well one thing we can do is come up with a file naming convention or some
> string in the header file to parse that would cause the commit check to
> permit the commit even if there are STL headers. But that is rather dubious
> as then anyone can just use whatever we come up with rather than just
> following the convention in the first place. Dave Thompson example (files
> named vtk*Private.h") can be easily implemented, but that won't help all
> cases.
> Or maybe it is time to revise the coding standards? I don't know what the
> correct process is for doing this though.
>
> On Fri, Jun 5, 2009 at 9:47 PM, Berk Geveci <berk.geveci at kitware.com> wrote:
>>
>> Is there a way of by-passing this commit check? There are a rare
>> occasions where it may be necessary to commit code which include STL
>> headers in .h files.
>>
>> To remind everyone why the decision to keep STL headers from include
>> files was made: performance. STL headers are bulky and may slow down
>> compilation significantly if they are included in header files that
>> are included by a lot of other files. Including STL headers in the
>> include files of leaf classes (such as concrete algorithm classes)
>> does not have any effect on compilation time. There are no other good
>> reasons why STL headers cannot be included in header files.
>>
>> Here is the catch: we occasionally receive contributions that include
>> STL header in .h. These tend to be super big reader classes. Fixing
>> the whole darn thing to use PIMPL is a waste of time which we don't
>> have. So, if we do not provide a way of having exception to this rule,
>> those contributions would never make it into VTK.
>>
>> So we should either provide a way of by-passing this commit check in
>> these rare occasions or we should enforce this through a header test
>> which can support such exceptions.
>>
>> -berk
>>
>> On Fri, Jun 5, 2009 at 5:13 PM, Francois
>> Bertel<francois.bertel at kitware.com> wrote:
>> > Isn't already enforced by HeaderTesting-* tests ?
>> >
>> > PS: I continue the discussion on vtk-developers only as this is the
>> > canonic place to discuss about this topic.
>> >
>> > On Fri, Jun 5, 2009 at 4:42 PM, Dave Partyka<dave.partyka at kitware.com>
>> > wrote:
>> >> Hi everyone,
>> >> A new CVS commit check has been added to prevent commits of VTK header
>> >> files
>> >> that contain STL includes. Exceptions can be added by contacting myself
>> >> or
>> >> Brad King.
>> >> I also want to give a friendly reminder that the VTK coding standards
>> >> (VTK
>> >> has coding standards???) provide guidelines for using STL in VTK and
>> >> require
>> >> that STL not be used in header files. See the following for more
>> >> information
>> >> or feel free to ask me if you have any questions.
>> >> VTK Coding Standards:
>> >> http://www.vtk.org/Wiki/VTK_Coding_Standards
>> >> VTK FAQ regarding STL
>> >> http://www.vtk.org/Wiki/VTK_FAQ#Can_I_use_STL_with_VTK.3F
>> >> Also please report any problems/bugs with the new commit check to
>> >> myself or
>> >> Brad King.
>> >> Thanks very much!
>> >
>> >
>> >
>> > --
>> > François Bertel, PhD  | Kitware Inc. Suite 204
>> > 1 (518) 371 3971 x113 | 28 Corporate Drive
>> >                      | Clifton Park NY 12065, USA
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